Revox B760 - Page 39

5.6.
Messen
der
Obersprechdampfung
Messgerate:
—
Mess-Sender,
Frequenz
97 MHz, EMK
2
mV, moduliert
mit Stereo-Modulator,
Hub 40
kHz,
Modulationsfrequenz
1 kHz,
(L= R), Pilotton
9%
(Hub
6,75
kHz).
—
1
5 kHz-Tiefpassfilter
—
Klirrfaktor-Messgerat
(oder Tonfre-
quenz-Millivoltmeter).
5.6.1.
Tuner: Mess-Sender-
Frequenz
abstimmen, bis
Instrument
TUNING
(J)
Null anzeigt
(ca.
97
MHz).
5.6.2.
Kl
i
rrfa
ktor- Messgerat
(oder
Tonfrequenz-Milli-
voltmeter) auf 0
dB eichen.
5.6.3.
Modulation
linker (bzw. rechter)
Kanal
abschal-
ten; Gbersprechen
vom rechten (bzw.
linken)
Kanal messen.
Die Obersprechdampfung soil
mehr
als 42
dB betragen.
5.6.
Stereo
separation
(crosstalk)
Test equipment:
—
R
F
generator,
frequency
97 MHz 2
mV
o.c.v.
Left and right channels
modulated
in
parallel
( L
=
R)
with 1 kHz
plus pilot
tone
to
40
kHz deviation.
—
Low-pass
filter 1
5
kHz
—
Distortion
meter (or
AC
millivoltmeter)
5.6.1.
Tuner:
Fine-tune
frequency
on
RF generator
to
obtain
an exact
center
indication
on
the
meter
TUNING
@
(97
MHz).
5.6.2.
Calibrate
distortion
meter
or AC millivoltmeter
to obtain
a
0
dB reference reading.
5.6.3.
Turn off
modulation
in the
left
channel
(or
right
channel
respectively)
and read
signal level
which
crosstalks
into the
other
channel.
The
crosstalk
figure
must be better
than
42
dB.
5.6.
Mesure de
I'affaiblissement
de
la
diaphonie
Appareils de
mesure:
—
Generateur:
97 MHz,
f.e.m.
2 mV. Mo-
dulateur
stereo:
excursion 40
kHz,
fre-
quence
de modulation
1 kHz,
(L=
R),
frequence
pilote
9
%
(excursion
6,75
kHz).
—
Filtre
passe-bas
de
1
5
kHz.
—
Distorsiometre
(ou
millivoltmetre
BF).
5.6.1.
Tuner: Ajustez
la
frequence du
generateur
jusqu'a
ce
que
I'instrument
TUNING
in-
dique
“0"
(97
MHz environ).
5.6.2.
Calibrez
a 0 dB le distorsiometre
(ou millivolt-
metre BF).
5.6.3.
Coupez
la modulation
du canal gauche
(resp.
droit) et
mesurez
I'affaiblissement
de la dia-
phonie du
canal droit (resp.
gauche). L'affaiblis-
sement
doit
etre
superieur
a
42
dB.
5.7. Messen
des Frequenzganges
Messgerate:
—
Mess-Sender, Frequenz
97
MHz,
EM
K
2 mV, moduliert
mit
Stereo-Modulator,
Hub 40
kHz,
Modulationsfrequenz
1
kHz, ohne
Pilotton.
—
Kl i rrfa ktor-Messgerat
(oder
Tonfre-
quenz-Millivoltmeter).
5.7.1.
Tuner:
Mess-Sender-
Frequenz
abstimmen,
bis
Instrumient
TUNING
(^
Null anzeigt
(ca.
97
MHz).
5.7.2.
Klirrfaktor-Messgerat
(oder
Tonfrequenz-Milli-
voltmeter)
auf 0 dB
eichen.
5.7.3.
Modulationsfrequenz
einstellen
auf:
30 Hz,
Abweichung:
0
dB
±
1
dB
1
5
kHz,
Abweichung:
—1
3,5
dB
±
1
dB
(De-emphasis
50
jus).
5.7. Frequency response
Test equipment:
—
RF generator,
frequency
97
MHz,
2
mV
o.c.v.
Modulate
with 1 kHz
to
40
kHz
deviation,
no
pilot tone.
—
Distortion
meter (or
AC millivoltmeter)
5.7.1.
Fine-tune
frequency on
RF
generator
to obtain
an
exact
center indication
on the
meter
TUNING
(^.
5.7.2.
Calibrate
distortion
meler
(or
AC millivolt-
meter)
to obtain
a 0
dB reference reading.
5.7.3.
Change
modulating
frequency
to:
30 Hz:
Output
must remain
within
±
1
dB
of
1
kHz
reference
15 kHz:
Output
at
50
jus
de-emphasis
=
—
13,5dB;
output
at
75
jus de-emphasis
=
-17
dB
5.7. Mesure
de la
bande
passante
Appareils de mesure:
—
Generateur: 97
MHz,
f.e.m. 2
mV. Mo-
dulateur stereo: excursion 40 kHz,
fre-
quence de modulation 1 kHz,
sans fre-
quence pilote.
—
Distorsiometre
(ou
millivoltmetre
BF).
5.7.1.
Tuner:
Ajustez
la frequence
du generateur
jusqu'a
ce que I'instrument
TUNI
NG in-
dique
"0"
(97
MHz
environ).
5.7.2.
Calibrez
a
0
dB le distorsiometre (ou millivolt-
metre BF).
5.7.3.
Reglez
la
frequence
de modulation
a:
30 Hz,
tolerance: 0
dB
±
1
dB
1
5
kHz,
tolerance:
—1
3,5
dB
±
1 dB
(desaccentuation
50
jus).
5-5